FIGS. 10(A) and (B) show one example of an electric connection box having the conventional cassette relay block attachment structure, for example, as shown in Unexamined Japanese Patent Publication 2003-125516.
This cassette relay block 72, as shown in an enlarged view shown in a circle in FIG. 10 (B), is formed of insulation resin and nearly in the shape of a rectangular parallelepiped externally, and has plural terminal housing rooms 74 for inserting and fixing female terminals 73 (FIG. 11) from the downside in its required positions; and lock arms 75 for a connection box body 79 are provided respectively on outer wall surfaces on both sides of the cassette relay block 72. The terminal housing room 74 continues to a relay terminal insertion hole located on the upside. The cassette relay block 72 in this example has two different relay insertion parts 81 and 82.
As shown in FIG. 11, into the female terminal 73 in the terminal housing room 74, a male terminal 77 of a relay 76 is inserted and connected. The female terminal 73 is pressure-connected to an electric wire 78, and the electric wire 78 is, for example, connected to a fuse in the connection box body 79 or an external load. In place of the electric wire in the connection box body 69, a bus bar may be used.
As shown in FIG. 10(A), to the connection box body 79 made of synthetic resin, plural kinds of cassette relay blocks 72 are fixed by the lock arms 75. The connection box body 79 has an insertion hole for the cassette relay block 72, and a fitting projection (not shown) for the lock arm 75 on an inner wall surface of the insertion hole 83.
Onto an electric connection box 71, in addition to the cassette relay block 72, electric parts such as a fuse and the like are frequently mounted. The connection box body 79, the plural cassette relay blocks 72, and the fuse (at least the connection box body 79 and the plural cassette relay blocks 72) constitute the electric connection box 71.
However, in the above conventional cassette relay block attachment structure, the lock arm protrudes from the outer wall surface of the cassette relay block, and protrudes outward more greatly than the external form of the relay that is the electric part. Therefore, since the large lock space is required, there is a problem that the cassette relay block and the connection box body for housing the cassette relay block are made large. Further, since the connection box body and the plural kinds of cassette relay blocks must be resin-molded for each car type, various metal molds are required, so that there is a problem that many manufacturing costs and manufacturing delivery times are required.